Politicians often talk of receiving a "mandate" after being elected. This disingenuous and erroneous rhetoric does not allow for effective political debate. Winning an election does not come with the right to do whatever you want. Someone who is elected represents those who didn't vote for them as well.
Therefore, an optional section should be added to all elections, not to change the actual outcome, but simply be a separate option the voter could select that would read something like "under protest." The results would then show that candidate X won with 55% of the vote, 70% of those votes were "under protest." This way no candidate would be under the false perception they have a "mandate," unless it's true, and would approach the job accordingly.